Sleep is important for good health. Frequent disturbances during sleep or sleep fragmentation can have severe consequences including day-time sleepiness (with the attendant possibility of motor-vehicle accidents), poor mentation, memory problems, depression and hypertension. For example, a person with nasal congestion may snore to a point that it disturbs that person's ability to sleep. Similarly, people with SDB are also likely to disturb their partner's sleep. One known effective form of treatment for patients with SDB is nasal continuous positive airway pressure (nasal CPAP) applied by a blower (air pump or compressor) via a connecting hose and patient interface. In some forms the supply of air at positive pressure is delivered to both the nose and mouth. The positive pressure can serve as a “pneumatic splint” so as to prevent a collapse of the patient's airway during inspiration, thus preventing events such as snoring, apneas or hypopnoeas and in many cases, is effective in treating central and mixed apnea.
Such positive airway pressure may be delivered in many forms. For example, a positive pressure level may be maintained across the inspiratory and expiratory levels of the patient's breathing cycle at an approximately constant level. Alternatively, pressure levels may be adjusted to change synchronously with the patient's breathing cycle. For example, pressure may be set at one level during inspiration and another lower level during expiration for patient comfort. Such a pressure treatment system may be referred to as bi-level. Alternatively, the pressure levels may be continuously adjusted to smoothly change with the patient's breathing cycle. A pressure setting during expiration lower than inspiration may generally be referred to as expiratory pressure relief. An automatically adjusting device may increase the treatment pressure in response to indications of partial or complete upper airway obstruction. See U.S. Pat. Nos. 5,245,995; 6,398,739; 6,635,021; 6,770,037; 7,004,908; 7,141,021; 6,363,933 and 5,704,345.
Other devices are known for providing respiratory tract therapy. For example, Schroeder et al. describes an apparatus for delivering heated and humidified air to the respiratory tract of a human patient in U.S. Pat. No. 7,314,046, which was filed on 8 Dec. 2000 and assigned to Vapotherm Inc. Similarly, Genger et al. discloses an anti-snoring device with a compressor and a nasal air cannula in U.S. Pat. No. 7,080,645, filed 21 Jul. 2003 and assigned to Seleon GmbH.
Respiratory insufficiency affects millions of people. For patient's suffering from this condition, the lungs are unable to inspire sufficient oxygen or expel sufficient carbon dioxide to meet the needs of the cells of the patient's body. For example, Chronic Obstructive Pulmonary Disease (“COPD”) affects approximately thirteen million Americans and ten million Europeans. COPD is a disease involving some damage to the lungs. The airways and the alveoli of the lungs can lose their elastic quality. Walls between alveoli can become destroyed or they can become inflamed. The airways of the lungs may also produce more mucus than usual, which can restrict airflow. This damage will typically manifest itself in some difficulty with breathing such as dyspnea. COPD patients typically experience coughing, with an expulsion of mucus, shortness of breath, wheezing and a feeling of tightness in the chest. Emphysema and chronic obstructive bronchitis may each be considered to be a form of COPD. Chronic obstructive bronchitis may be characterized by an inflammatory response in the larger airways of the lungs. Emphysema may be characterized by destruction of tissue of the lungs from an inflammatory response.
There is no presently known cure for COPD. There is no treatment for restoring the airways and alveoli of the lungs of a COPD patient to their pre-disease condition. However, treatments and lifestyle changes can help a COPD patient to feel more comfortable, continue to be active and impede the progression of the disease.
It will be appreciated that there is a need in the art for improved techniques and devices for addressing the respiratory conditions of patients such as those suffering from SDB or respiratory insufficiency such as COPD.